Methods for managing co-located macro and femto base station deployments and methods for initiating mobile station handoff

ABSTRACT

In a method for managing a plurality of neighboring base stations and handoff of a mobile station, a radio frequency equipment organizes the plurality of neighboring base stations into groups according to base station grouping characteristics associated with the plurality of neighboring base stations. The radio frequency equipment then manages the organized plurality of neighboring base stations for handoff of the mobile station.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This non-provisional U.S. patent application claims priority under 35U.S.C. §119(e) to provisional patent application No. 61/274,983 filed onAug. 24, 2009, the entire contents of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

A femto base station is basically a low cost and low power base station(BS) transceiver, which is installed indoors (e.g., in a home oroffice). A femto base station is usually connected to the Internet viacable, a digital subscriber line (DSL), an on-premise fiber optic link,or a similar Internet Protocol (IP) backhaul technology. This connectionis used to integrate the femto base station with a wireless operator'score network.

A femto base station serves a geographic area known as a femto cell overa single carrier or channel. A femto cell typically covers a smallergeographic area or subscriber constituency than a conventional macrocell. For example, a femto base station typically provides radiocoverage in a geographical area such as a building or home, whereas aconventional macro base station provides radio coverage in a larger areasuch as an entire city or town. Femto cells may exist within or overlapmacro cells.

The function of a femto cell is similar to that of a Wireless Local AreaNetwork (LAN), and provides operators a relatively low cost solution forextending coverage areas and off-loading users from the cellularnetwork.

In conventional wireless femto base station deployments in multipletechnologies such as WiMAX, long term evolution (LTE),enhanced-voice-data-only (EVDO), etc., a relatively large number (e.g.,100 s) of femto base stations co-exist with macro base stations. But,conventional handoff methods based on neighbor base station scanningtypically performed by mobile stations are designed for a limited set ofneighbor macro base stations. Thus, these conventional methods are notadequate for scenarios having to deal with larger numbers of femto basestations in addition to the conventional macro base stations at leastbecause: (1) conventional scanning of all the potential target basestations drain the device battery; (2) limited space in the airinterface within the broadcast messages restricts inclusion of all thepotential base station details; and (3) relatively long scanning periodsof all the potential target base stations affect datatransmission/reception.

Moreover, the presence of larger numbers of neighbor base stations(e.g., macro and/or femto) also impedes efficient management of theseneighbors for potential handoff because reporting too many base stationsto the mobile station in an advertisement field is impractical.

SUMMARY OF THE INVENTION

Example embodiments relate to methods for managing femto and macro basestation co-deployments. Example embodiments also relate to methods forinitiating handoff of a mobile station in a wireless network includingfemto and macro base station co-deployments.

At least one example embodiment provides a method for managing aplurality of neighboring base stations and handoff of a mobile station.According to at least this example embodiment, a radio frequencyequipment organizes the plurality of neighboring base stations intogroups according to base station grouping characteristics associatedwith the plurality of neighboring base stations. The radio frequencyequipment then manages the organized plurality of neighboring basestations for handoff of the mobile station.

At least one other example embodiment provides a method for managing aplurality of neighboring base stations and initiating handoff of amobile station. According to at least this example embodiment, a radiofrequency equipment organizes the plurality of neighboring base stationsinto groups according to base station grouping characteristicsassociated with each of plurality of neighboring base stations, andadvertises each of the groups in an advertisement message. The radiofrequency equipment at least one of manages and initiates handoff of themobile station to a base station in an advertised group. Theadvertisement message includes a base station group identifieridentifying each of the groups, and each base station group identifieris at least one of indicative and representative of the base station,grouping characteristics associated with a corresponding group.

At least one other example embodiment provides a method for managing aplurality of neighboring base stations and initiating handoff of amobile station to one of the plurality of neighboring base stations.According to at least this example embodiment, a radio frequencyequipment organizes the plurality of neighboring base stations intogroups according to base station grouping characteristics associatedwith the plurality of neighboring base stations, and advertises each ofthe groups in la distinctive identifiable fashion in an advertisementmessage. The radio frequency equipment then at least one of manages andinitiates handoff of the mobile station to an advertised group. Theadvertisement message includes a base station group identifieridentifying each of the groups, and the base station group identifier isindicative of base station grouping characteristics associated with thegroups. The base station group identifier associated with each of thegroups is a base station identifier for a representative base stationwithin each group.

According to at least some example embodiments, the radio frequencyequipment may be the serving base station to which the mobile station iscurrently attached.

Example embodiments described herein provide for more efficientmanagement of larger numbers of neighbor base stations (e.g., macroand/or femto) for potential handoff.

Example embodiments described herein also improve device battery life,reduce consumption of limited space in the air interface for broadcastmessages, and/or reduce relatively long scanning periods of all thepotential target base stations affecting data transmission/reception.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given herein below and the accompanying drawings,wherein like elements are represented by like reference numerals, whichare given by way of illustration only and thus are not limiting of thepresent invention and wherein:

FIG. 1 illustrates a portion of a telecommunications network in whichexample embodiments may be implemented;

FIG. 2 is a flow chart illustrating a method for managing femto andmacro cell deployments according to an example embodiment; and

FIGS. 3 and 4 are diagrams for illustrating several steps of the methodshown in FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various example embodiments will now be described more fully withreference to the accompanying drawings in which some example embodimentsare illustrated.

Accordingly, while example embodiments are capable of variousmodifications and alternative forms, embodiments thereof are shown byway of example in the drawings and will herein be described in detail.It should be understood, however, that there is no intent to limitexample embodiments to the particular forms disclosed, but on thecontrary, example embodiments are to cover all modifications,equivalents, and alternatives falling within the scope of exampleembodiments. Like numbers refer to like elements throughout thedescription of the figures.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Spatially relative terms such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or a relationship between a feature and anotherelement or feature as illustrated in the figures. It will be understoodthat the spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, for example, the term “below” can encompass both anorientation which is above as well as below. The device may be otherwiseoriented (rotated 90 degrees or viewed or referenced at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, for example, those defined incommonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand will not be interpreted in an idealized or overly formal senseunless expressly so defined herein.

Portions of example embodiments and corresponding detailed descriptionare presented in terms of software, or algorithms and symbolicrepresentations of operation on data bits within a computer memory.These descriptions and representations are the ones by which those ofordinary skill in the art effectively convey the substance of their workto others of ordinary skill in the art. An algorithm, as the term isused here, and as it is used generally, is conceived to be aself-consistent sequence of steps leading to a desired result. The stepsare those requiring physical manipulations of physical quantities.Usually, though not necessarily, these quantities take the form ofoptical, electrical, or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It isconvenient at times, principally for reasons of common usage, to referto these signals as bits, values, elements, symbols, characters, terms,numbers, or the like.

In the following description, illustrative embodiments will be describedwith reference to acts and symbolic representations of operations (e.g.,in the form of flowcharts) that may be implemented as program modules orfunctional processes include routines, programs, objects, components,data structures, that perform particular tasks or implement particularabstract data types and may be implemented using existing hardware atexisting network elements or control nodes (e.g., a database). Suchexisting hardware may include one or more Central Processing Units(CPUs), digital signal processors (DSPs),application-specific-integrated-circuits, field programmable gate arrays(FPGAs) computers or the like.

It should be borne in mind; however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise, or as is apparent from the discussion,terms such as “processing” or “computing” or “calculating” or“determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical, electronicquantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

Note also that the software implemented aspects of example embodimentsare typically encoded on some form of computer readable medium orimplemented over some type of transmission medium. The computer readablemedium may be magnetic (e.g., a floppy disk or a hard drive) or optical(e.g., a compact disk read only memory, or “CD ROM”), and may be readonly or random access. Similarly, the transmission medium may be twistedwire pairs, coaxial cable, optical fiber, or some other suitabletransmission medium known to the art. Example embodiments are notlimited by these aspects of any given implementation.

Example embodiments are described herein in the context of WorldwideInteroperability for Microwave Access (WiMAX) femto deployments, but areintended to be broadly applicable to femto/macro co-location deploymentsgenerally.

FIG. 1 illustrates a portion of a telecommunications system in whichillustrative embodiments may be implemented. The telecommunicationssystem 10 is shown as a portion of a radio access network (RAN)including a macro cell 100M and a plurality of femto cells 100F, each ofwhich have different coverage areas. As shown, the plurality of femtocells 100F overlap with the coverage area of the macro cell 100M. InFIG. 1, the femto cells 100F are considered neighbors of the macro cell100M.

The RAN shown in FIG. 1 may include a RAN control node (not shown). TheRAN control node may be, for example, a radio network controller (RNC)in a hierarchical network architecture or a serving radio networkcontroller (SRNC) in a flat network. The RAN control node may be linkedwith a macro base station 102M via one or more packet and/or circuitswitched networks (e.g., one or more Internet Protocol (IP) networks orthe like). The macro base station 102M provides radio coverage in themacro cell 100M.

The RAN may also include a femto management system (FMS) (not shown).The FMS is analogous to and has the same functionality as a RAN controlnode in a Macro cellular system.

The FMS may maintain a separate link with each of a plurality of femtobase stations 102F via one or more packet and/or circuit switchednetworks (e.g., one or more Internet Protocol (IP) networks or thelike). The femto base stations 102F provide radio coverage in respectivefemto cells 100F. Although not specifically discussed herein, exampleembodiments may be implemented in connection with or applicable to picobase stations or micro base stations.

As discussed herein, the femto base stations, macro base stations and/ornetwork controllers may be referred to as radio frequency networkequipment/elements or RAN control nodes.

Other types of telecommunications systems which encompass other types ofradio access networks include the following: Universal MobileTelecommunications System (UMTS); Global System for Mobilecommunications (GSM); Advance Mobile Phone Service (AMPS) system; theNarrowband AMPS system (NAMPS); the Total Access Communications System(TACS); the Personal Digital Cellular (PDC) system; the United StatesDigital Cellular (USDC) system; the code division multiple access (CDMA)system described in EIA/TIA IS-95; Worldwide Interoperability forMicrowave Access (WiMAX); ultra mobile broadband (UMB); and long termevolution (LTE).

Referring still to FIG. 1, as is well-known, mobile station 104MScommunicates with one or more of femto base stations 102F and macro basestation 102M over an air interface. The mobile station 104MS may be, forexample, a mobile telephone (“cellular” telephone), a portable computer,pocket computer, hand-held computer, a personal digital assistant (PDA),a car-mounted mobile device or the like, which communicates voice and/ordata with the RAN.

For the sake of example, FIG. 1 shows only a few femto base stations102F, a few femto cells 100F, a single macro base station 102M, a singlemacro cell 100M and a single mobile station 104MS. However, it will beunderstood that RANs may include any number of base stations and cells(femto and macro), which serve any number of mobile stations.

Example embodiments provide methods for managing femto base station andmacro base station co-deployments, and/or overlay deployments. In oneembodiment, handoff of a mobile station from a macro base station to afemto base station is controlled by managing a number of candidate femtobase stations to which the mobile station may be handed off.

FIG. 2 is a flow chart illustrating a method for managing femto andmacro base station co-deployments and/or initiating handoff of a mobilestation according to an example embodiment. The example embodiment shownin FIG. 2 will be described assuming that the mobile station 104MS iscurrently being served by the macro base station 102M. In this example,the method shown in FIG. 2 is performed by the macro base station 102M.However, example embodiments are also applicable to situations in whichthe mobile station 104MS is served by a femto base station 102F or otherbase station (e.g., a pico base station, a micro base station, etc.). Inthis alternative example, the method shown in FIG. 2 is performed by thefemto base station 102F. The method shown in FIG. 2 may also beperformed at a RAN control node (e.g., an RNC) or base stationcontroller.

Referring to FIG. 2, at step S210 the macro or pico base station 102Morganizes the neighboring femto base stations 102F into certainidentifiable groups (referred to as “femto groups”) based on femtogrouping characteristics. Each of the femto groups includes at least onefemto base station. The femto grouping characteristics are associatedwith each of the femto base stations 102F, and consequently with thefemto groups. Femto grouping characteristics may include, for example:radio frequency (RF) characteristics; geographic locationcharacteristics (e.g., neighborhood, street, apartments, etc.); femtopaging groups; Frequency Assignment (FA index); unique preamble sequence(an example preamble is described in section 8.4.6.1.1 of “PART 16: AIRINTERFACE FOR BROADBAND WIRELESS ACCESS SYSTEMS” of the 802.16 by IEEEfrom January 2009, but example embodiments should not be limited to thisexample) any subset of the unique preamble sequence or unique preamblesequences; Internet Protocol (IP) address subnet; or other logicaltraits. FIG. 3 illustrates a plurality of femto cells 102F organizedinto a plurality of femto groups G1 through G6.

In the example shown in FIG. 3, the macro base station 102M groups theplurality of femto base stations 102F into a plurality of femto groupsG1 through G6 as described above with regard to step S210 shown in FIG.2.

Referring back to FIG. 2, at steps S212 through S226, the macro basestation 102M manages the organized plurality of neighboring basestations for handoff of the mobile station. Although the managing stepis described as including steps S212 through S226 in FIG. 2, accordingto example embodiments the managing step may encompass one or more ofsteps S212 through S226 shown and described with regard to FIG. 2.

More specifically, at step S212 the macro base station 102M assigns arepresentative base station identifier (BSID) to each femto group (e.g.,each of femto groups G1 through G6 shown in FIG. 3). The BSID (alsoreferred to as a base station group identifier) is at least one ofindicative and representative of, for example, the femto groupingcharacteristics associated with a given femto group. In one example, theassigned base station group identifier for each group is not a BSID fora base station within the corresponding group.

Alternatively, at step S212, the macro base station 102M selects a femtobase station in each femto group as a representative femto base station.In this example, the BSID for the selected femto base station is used asthe base station group identifier identifying the respective femto groupthat may also include a femto base station identified by a different andunique BSID.

FIG. 4 shows a plurality of femto base stations for illustrating severalsteps of the method shown in FIG. 2. In one aspect, FIG. 4 shows a casein which the macro base station 102M selects a femto base station fromeach femto group as a representative femto base station.

Returning to FIG. 2, at step S214 the macro base station 102M advertisesits respective neighbors in an advertisement message. In one example,the advertisement message is a neighbor advertisement message such asthe NBR-ADV message described in “PART 16: AIR INTERFACE FOR BROADBANDWIRELESS ACCESS SYSTEMS” of the 802.16 by IEEE from January 2009, theAAI_NBR-ADV message described in section 16.2.3.12 of the IEEE P802.16mDRAFT Amendment to IEEE Standard for Local and Metropolitan AreaNetworks, any broadcast advertisement message or broadcast information.In this example, the macro base station 102M advertises each of thefemto groups in an advertisement message including the base stationgroup identifier assigned to each of the groups.

Still referring to FIG. 2, at step S216 the macro base station 102Mcauses the initiation of a scan of neighboring base stations in responseto a request from the mobile station 104MS. The scan is performed over ascanning interval. In this example, the macro base station 102M receivesthe scan request from the mobile station 104MS in response to theadvertisement message. Alternatively, the mobile station 104MS mayinitiate the scan of neighboring base stations in response to theadvertisement message, any broadcast advertisement message or broadcastinformation.

To initiate the scan, the macro base station 102M generates a list ofbase stations to be scanned by the mobile station 104MS in response tothe scan request from the mobile station 104MS, and sends the generatedscan list to the mobile station 104MS.

In one example, if a BSID is used to identify a femto group, the scanlist is a temporary list of allowed base stations from the neighboringfemto base stations. The scan list may be generated from the advertisedlist and/or based on previously reported received valid signal strengthindicator (RSSI) values for femto base stations, and instructs themobile station to scan for other base stations from one or more femtogroups.

In response to the scan list from the macro base station 102M, themobile station 104MS scans at least one femto base station belonging toeach femto group to identify at least one valid femto group. In thisstep, the mobile station 104MS also scans the femto base stations ineach femto group to determine available neighbor femto base stationinformation, and acquire measurements regarding the femto base stationsin each femto group. The acquired measurements may include, for example,base station received signal strength indicator (BS RSSI) values, basestation carrier to interference and noise ratio (BS CINR), relativedelay, round trip delay (RTD), expected packet error rate (PER), etc.The mobile station 104MS then reports the valid femto groups, acquiredinformation and measurements to the serving macro base station 102M.

In one example, the mobile station 104MS continues to scan at least onefemto base station in each group of allowed femto base stations until avalid femto group is detected. As discussed herein, a “valid femtogroup” for a mobile station includes at least one femto base station,where the mobile station is a subscriber and the mobile station isallowed entry and service. A typical example of this is a mobile stationsubscriber of a household and the femto base station of the house or aneighborhood of apartments. Non-subscribers of the valid femto group maybe denied entry and service, while a subscriber mobile station will berecognized (e.g., based on the mobile station identifier (MSID) andsubscriber list) and provided service. Such femto groups are referred toas Closed Subscriber Groups (CSG). But, under a macro base station,there may be base stations, which do not belong to any particulargroups. These open groups are ‘open’ for all subscribers. Hence, a validbase station may be any base station from a CSG, the mobile stationsubscribership or any open femto base station.

Still referring to FIG. 2, at step S218 the macro base station 102Mreceives the scan results, acquired measurements and determined validfemto group(s) from the mobile station 104MS.

At step S220, the serving macro base station 102M determines whether themobile station 104MS is in the vicinity of any valid femto group basedon the scan results reported by the mobile station 104MS. In thisexample, a reported non-zero RSSI value for a particular valid femtogroup indicates that the mobile station 104MS is in the vicinity of thevalid femto group. As discussed herein, a valid femto base station inthe vicinity of the mobile station 104MS is referred to as a potential“target femto base station,” and a valid femto group in the vicinity ofthe mobile station 104MS is referred to as a potential “target femtogroup.”

According to example embodiments, the macro base station 102M mayidentify valid femto groups or valid femto base stations as target femtogroups or target femto base stations based on the subscribership of themobile station 104MS and the proximity of the mobile station 104MS(e.g., indicated by the RSSI value of a member base station in the scanreport message) to the femto group. If a BSID is used to represent afemto group in the above-described advertisement message, the mobilestation 104MS may report information about multiple members of the femtogroup indicating that the mobile station 104MS is approaching a targetfemto base station or target femto group for potential handoff.

Still referring to FIG. 2, if the macro base station 102M determinesthat the mobile station 104MS is not in the vicinity or proximity of anyvalid femto group, the process returns to step S216 and continues asdiscussed herein. In this example, the mobile station 102MS iterativelyscans the organized plurality of neighboring base stations if the macrobase station 102M determines that the mobile station 104MS is not in thevicinity or proximity of any valid femto group.

Returning to step S220, if the macro base station 102M identifies atleast one target femto group, at step S221 the macro base station 102Mdetermines whether any allowed femto base stations correspond to targetfemto base stations in the one or more target femto groups identified atstep S221. As discussed herein, those femto base stations considered asboth allowed and target femto base stations are referred to as“candidate femto base stations.” In one example, the macro base station102M compares BSIDs of the allowed femto base stations with BSIDs of thetarget femto base stations to determine the candidate femto basestations or candidate femto group(s).

If the macro base station 102M identifies one or more candidate femtobase stations at step S221, then at step S222 the macro base station102M compares a received signal strength indicator value RSSI_(FBS) foreach of the identified candidate femto base stations with a signalstrength indicator threshold value RSSI_THRESH. In one example, thereceived signal strength indicator values are received signal strengthindicators (RSSI) and/or carrier to interference and noise ratio (CINR)reported to the macro base station 102M by the mobile station 104MS.And, the signal strength indicator threshold is an RSSI threshold.

If the received signal strength indicator value RSSI_(FBS) for one ormore of the candidate femto base stations passes the signal strengthindicator threshold, the macro base station 102M initiates handoff ofthe mobile station 104MS to one of the candidate femto base stationshaving a received signal strength indicator value RSSI_(FBS) that passesthe signal strength indicator threshold at step S224. The mobile station104MS is then handed off to the candidate femto base station as is knownin the art.

According to example embodiments, a received signal strength indicatorvalue RSSI_(FBS) passes the signal strength indicator threshold if thereceived signal strength indicator value RSSI_(FBS) is greater than orequal to the signal strength indicator threshold value RSSI_THRESH.

If more than one candidate femto base station has a received signalstrength indicator value RSSI_(FBS), which is greater than or equal tothe signal strength indicator threshold value RSSI_THRESH, the macrobase station 102M selects one of the candidate femto base stations towhich to hand off the mobile station 104MS. In one example, the macrobase station 102M selects the candidate femto base station associatedwith the highest received signal strength indicator value RSSI_(FBS). Inanother example, the macro base station 102M selects the candidate femtobase station based on a loading of the candidate femto base stations. Inyet another example, the macro base station 102M selects the candidatefemto base station based on an expected packet error rate (PER).

Returning to step S222, if none of the candidate femto base stations hasa received signal strength indicator value RSSI_(FBS) greater than orequal to the signal strength indicator threshold value RSSI_THRESH, atstep S226 the macro base station 102M refines the scan list to thetarget base stations identified at step S220. In one example, the macrobase station 102M refines the scan list of base stations at the mobilestation 104MS by sending a scan list update message to the mobilestation 104MS. The scan list update message may be a SCAN-RSP messageidentifying at least a portion of the allowed base stations.

After refining the scan list at step S226, the process returns to stepS221 and proceeds as discussed above.

Returning to step S221, if no allowed femto base stations correspond toidentified target femto base stations, the method proceeds to step S226and continues as discussed above.

Example embodiments provide a more manageable target list of basestations in portions of a wireless communication network including macroand femto base stations.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the invention, and all such modifications are intended tobe included within the scope of the invention.

We claim:
 1. A method for managing a plurality of neighboring basestations and handoff of a mobile station, the method comprising:organizing, by a radio frequency equipment, the plurality of neighboringbase stations into groups according to base station groupingcharacteristics associated with the plurality of neighboring basestations; transmitting, by the radio frequency equipment, anadvertisement message including a plurality of base station groupidentifiers such that each base station, upon receiving theadvertisement message, is notified of a group to which the base stationbelongs as well as remaining ones of the plurality of base station groupidentifiers for other groups of base stations, each of the plurality ofbase station group identifiers identifying one of the groups; andmanaging the handoff of the mobile station to a base station in anadvertised group.
 2. The method of claim 1, wherein the base stationgrouping characteristics include at least one of radio frequencycharacteristics associated with the plurality of neighboring basestations, geographic location characteristics associated with theplurality of neighboring base stations, base station paging groups,Frequency Assignment, and Internet Protocol address subnet for themobile station.
 3. The method of claim 2, wherein the radio frequencycharacteristics include at least one of frequency assignment, uniquepreamble sequence, and cyclic prefix.
 4. The method of claim 1, furthercomprising: assigning, by the radio frequency equipment, one of theplurality of base station group identifiers to each group of basestations based on the associated base station grouping characteristics;wherein the transmitting step includes, advertising, by the radiofrequency equipment, each of the groups in the advertisement message. 5.The method of claim 1, wherein the advertisement message is an NBR-ADVor an AAI_NBR-ADV message.
 6. The method of claim 1, further comprising:selecting a base station in each group as a representative base station;wherein the transmitting step includes, advertising, by the radiofrequency equipment, each of the groups in the advertisement message,the base station group identifier for each group is a base stationidentifier for the selected base station, and the base stationidentifier is at least one of indicative and representative of basestation grouping characteristics.
 7. The method of claim 6, wherein theadvertisement message is an NBR-ADV or an AAI_NBR-ADV message.
 8. Amethod for managing a plurality of neighboring base stations andinitiating handoff of a mobile station, the method comprising:organizing, by a radio frequency equipment, the plurality of neighboringbase stations into groups according to base station groupingcharacteristics associated with each of plurality of neighboring basestations; advertising, by the radio frequency equipment, each of thegroups in an advertisement message, the advertisement message includinga plurality of a base station group identifiers such that each basestation, upon receiving the advertisement message, is notified of agroup to which the base station belongs as well as remaining ones of theplurality of base station group identifiers for other groups of basestations, each of the plurality of base station group identifiersidentifying one of the groups based on the base station groupingcharacteristics associated with a corresponding group; and at least oneof managing and initiating, by the radio frequency equipment, handoff ofthe mobile station to a base station in an advertised group.
 9. Themethod of claim 8, wherein the base station group identifier for eachgroup is not a base station identifier for a base station in thecorresponding group.
 10. The method of claim 8, further comprising:selecting a base station in each group as a representative base station;wherein the base station group identifier for each group is a basestation identifier for the selected base station.
 11. The method ofclaim 8, wherein the advertisement message is an NBR-ADV or anAAI_NBR-ADV message.
 12. The method of claim 8, wherein the at least oneof managing and initiating steps comprises: determining, by a radiofrequency equipment, whether the mobile station is in a vicinity of atleast one of the organized plurality of neighboring base stations;comparing, by the radio frequency equipment, a received signal strengthindicator with a signal strength indicator threshold, the receivedsignal strength indicator being associated with the at least oneneighboring base station; and initiating, by the radio frequencyequipment, handoff of the mobile station to the at least one neighboringbase station if the received signal strength indicator passes the signalstrength indicator threshold.
 13. The method of claim 12, wherein the atleast one of managing and initiating steps comprises: generating, by theradio frequency equipment, a list of base stations in response to a scanrequest message from the mobile station, the scan list including atemporary list of allowed base stations among the organized plurality ofneighboring base stations, the allowed list of base stations beinggenerated based on reported signal strength indicator values associatedwith the organized plurality of neighboring base stations; initiating,by the radio frequency equipment, a scan of the organized plurality ofneighboring base stations in response to a request for a scanninginterval from the mobile station; and wherein the determining stepdetermines whether the mobile station is in the vicinity of at least oneof the organized plurality of neighboring base stations based on scanresults and measurements acquired during the scan.
 14. The method ofclaim 12, wherein the at least one of managing and initiating stepscomprises: initiating, by the mobile station a scan of the organizedplurality of neighboring base stations in response to the advertisementmessage; and wherein the determining step determines whether the mobilestation is in the vicinity of at least one of the organized plurality ofneighboring base stations based on scan results and measurementsacquired during the scan.
 15. The method of claim 12, furthercomprising: iteratively scanning, by the mobile station, the organizedplurality of neighboring base stations if the determining stepdetermines that the mobile station is not in the vicinity of at leastone of the organized plurality of neighboring base stations.
 16. Themethod of claim 12, further comprising: determining whether the at leastone neighboring base station corresponds to an identified valid basestation if the radio frequency equipment determines that the mobilestation is in the vicinity of a valid base station group; and whereinthe comparing step compares the received signal strength indicatorassociated with the at least one neighboring base station with a signalstrength indicator threshold if the at least one neighboring basestation corresponds to the identified valid base station; wherein thevalid base station group is a group of base stations of which the mobilestation is a subscriber and the mobile station expects entry andservice.
 17. The method of claim 12, wherein if a plurality ofneighboring base stations have received signal strength indicatorspassing the signal strength indicator threshold, the method furthercomprises: selecting, by the radio frequency equipment, the base stationhaving a highest received signal strength indicator as the base stationto which the mobile station is to be handed off; and wherein theinitiating step initiates handoff of the mobile station to the selectedbase station.
 18. The method of claim 12, wherein if a plurality ofneighboring base stations have received signal strength indicatorspassing the signal strength indicator threshold, the method furthercomprises: selecting, by the radio frequency equipment, the valid targetbase station based on a loading of the base stations; and wherein theinitiating step initiates handoff of the mobile station to the selectedvalid base station.
 19. The method of claim 12, wherein if a pluralityof neighboring base stations have received signal strength indicatorspassing the signal strength indicator threshold, the method furthercomprises: selecting, by the radio frequency equipment, the valid targetbase station based on an expected packet error rate; and wherein theinitiating step initiates handoff of the mobile station to the selectedvalid base station.
 20. A method for managing a plurality of neighboringbase stations and initiating handoff of a mobile station to one of theplurality of neighboring base stations, the method comprising:organizing, by a radio frequency equipment, the plurality of neighboringbase stations into groups according to base station groupingcharacteristics associated with each of plurality of neighboring basestations; advertising, by the radio frequency equipment, each of thegroups in an advertisement message, the advertisement message includinga plurality of base station group identifiers such that each basestation, upon receiving the advertisement message, is notified of agroup to which the base station belongs as well as remaining ones of theplurality of base station group identifiers for other groups of basestations, each of the plurality of base station group identifiersidentifying one of the groups based on the base station groupingcharacteristics associated with a corresponding group; and at least oneof managing and initiating, by the radio frequency equipment, handoff ofthe mobile station to a base station in an advertised group; wherein thebase station group identifier associated with each of the groups is abase station identifier for a representative base station within eachgroup.
 21. The method of claim 20, wherein the at least one of managingand initiating steps comprises: determining, by a radio frequencyequipment, whether the mobile station is in a vicinity of at least oneof the plurality of neighboring base stations; comparing, by the radiofrequency equipment, a received signal strength indicator with a signalstrength indicator threshold, the received signal strength indicatorbeing associated with the at least one neighboring base station; andinitiating, by the radio frequency equipment, handoff of the mobilestation to the at least one neighboring base station if the receivedsignal strength indicator passes the signal strength indicatorthreshold.
 22. The method of claim 21, further comprising: determiningwhether the at least one neighboring base station corresponds to anidentified valid base station if the radio frequency equipmentdetermines that the mobile station is in the vicinity of a valid basestation group; and wherein the comparing step compares the receivedsignal strength indicator associated with the at least one neighboringbase station with the signal strength indicator threshold if the atleast one neighboring base station corresponds to the identified validbase station; wherein the valid base station group is a group of basestations of which the mobile station is a subscriber and the mobilestation expects entry and service.
 23. The method of claim 21, whereinif a plurality of neighboring base stations have received signalstrength indicators passing the signal strength indicator threshold, themethod further comprises: selecting, by the radio frequency equipment,the base station having a highest received signal strength indicator asthe base station to which the mobile station is to be handed off; andwherein the initiating step initiates handoff of the mobile station tothe selected base station.
 24. The method of claim 21, wherein if aplurality of neighboring base stations have received signal strengthindicators passing the signal strength indicator threshold, the methodfurther comprises: selecting, by the radio frequency equipment, thevalid target base station based on a loading of the base stations; andwherein the initiating step initiates handoff of the mobile station tothe selected valid base station.
 25. The method of claim 21, wherein ifa plurality of neighboring base stations have received signal strengthindicators passing the signal strength indicator threshold, the methodfurther comprises: selecting, by the radio frequency equipment, thevalid target base station based on an expected packet error rate; andwherein the initiating step initiates handoff of the mobile station tothe selected valid base station.